T cells in chronic rhinosinusitis with nasal polyposis

Pathogenesis of Nasal Polyposis: Current Trends

Chronic Rhinosinusitis (CRS) is characterized by edema of the sub-epithelial layers, but, only specific types of CRS are developing polyps. Nasal polyposis may develop under different pathogenetic mechanisms rendering the typical macroscopic classification of CRS, with or without nasal polyps, rather deficient. Currently, we approach nasal polyposis, in terms of diagnosis and treatment, according to its endotype, which means that we focus on the specific cells and cytokines that are participating in its pathogenesis. It appears that the molecular procedures that contribute to polyp formation, initiating with a Th-2 response of the adaptive immune system, are local phenomena occurring in the sub-epithelial layers of the mucosa. Several hypotheses are trying to approach the etiology that drives the immune response towards Th-2 type. Extrinsic factors, like fungi, Staphylococcus superantigens, biofilms, and altered microbiome can contribute to a modified and intense local reaction of the immune system. Some hypotheses based on intrinsic factors like the elimination of Treg lymphocytes, low local vitamin-D levels, high levels of leukotrienes, epithelial to mesenchymal transition (EMT) induced by hypoxia, and altered levels of NO, add pieces to the puzzle of the pathogenesis of nasal polyposis. Currently, the most complete theory is that of epithelial immune barrier dysfunction. Intrinsic and extrinsic conditions can damage the epithelial barrier rendering sub-epithelial layers more vulnerable to invasion by pathogens that trigger a Th-2 response of the adaptive immune system. Th2 cytokines, subsequently, induce the accumulation of eosinophils and IgE together with the remodeling of the stroma in the sub-epithelial layers leading, eventually, to the formation of nasal polyps.

Exosomes Represent an Immune Suppressive T Cell Checkpoint in Human Chronic Inflammatory Microenvironments

Background: T cells present in chronic inflammatory tissues such as nasal polyps (from chronic rhinosinusitis patients) have been demonstrated to be hypo-responsive to activation via the TCR, similar to tumor-specific T cells in multiple different human tumor microenvironments. While immunosuppressive exosomes have been known to contribute to the failure of the tumor-associated T cells to respond optimally to activation stimuli, it is not known whether they play a similar role in chronic inflammatory microenvironments. In the current study, we investigate whether exosomes derived from chronic inflammatory microenvironments contribute to the immune suppression of T cells. Methods: Exosomes were isolated by ultracentrifugation and characterized by size and composition using nanoparticle tracking analysis, scanning electron microscopy, antibody arrays and flow exometry. Immunosuppressive ability of the exosomes was measured by quantifying its effect on activation of T cells, using nuclear translocation of NFκB as an activation endpoint. Results: Exosomes were isolated and characterized from two different types of chronic inflammatory tissues - nasal polyps from chronic rhinosinusitis patients and synovial fluid from rheumatoid arthritis patients. These exosomes arrest the activation of T cells stimulated via the TCR. This immune suppression, like that which is seen in tumor microenvironments, is dependent in part upon a lipid, ganglioside GD3, which is expressed on the exosomal surface. Conclusion: Immunosuppressive exosomes present in non-malignant chronic inflammatory tissues represent a new T cell checkpoint, and potentially represent a novel therapeutic target to enhance the response to current therapies and prevent disease recurrences.

Evaluation of the frequency of invariant natural killer T (iNKT) cells in nasal polyps

Nasal polyps (NP) are associated with inflamed mucosa of unknown etiology. The role of T cells in nasal polyposis is unclear. Invariant natural killer T cells (iNKT) can promote Th2 responses and have been implicated in some types of asthma. As there are shared inflammatory pathways involved in asthma and NPs, we evaluated the frequency of iNKT in 17 patients with NPs, but without asthma. A median of 6% polyp cells were T lymphocytes, of which iNKT were 0 to 2.38% (mean 0.674%). In the matched group (n = 10), iNKT in NPs was significantly higher than PBMCs (1.057% vs 0.155%, P < 0.05). Relative expression of Vα24 to TCR-beta genes in polyps (n = 14) was higher than blood in matched samples (n = 4). The presence of greater proportions of iNKT in NPs than in blood suggests that iNKT may play a role in the pathogenesis of nasal polyposis.

Acquired Immunity in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a prevalent disease that is associated with significant costs and quality of life impairments. Currently, patients are classified into subgroups based on clinical characteristics, most often the presence or absence of nasal polyps. However, despite medical and surgical treatment, many of these patients continue to have symptoms. Recent efforts have focused on gaining a more complete understanding of the inflammatory mechanisms that drive pathogenesis in CRS, and it is becoming clear that the inflammatory processes in CRS are quite complex. As our understanding of these complex phenotypes improves, it may become possible to classify patients into endotypes based on unique inflammatory patterns within the sinus mucosa. This information may also lead to the identification of appropriate targeted therapies for different endotypes. This review will discuss our current understanding of endotypes in CRS along with the unique adaptive immune responses that may contribute to these different endotypes and, finally, some potential targeted therapeutics for the next generation of CRS treatment strategies.

Interleukin-17A expression in patients presenting with nasal polyposis

Sinonasal polyposis (SNP) is a chronic inflammatory pathology of the nasal/paranasal cavities which affects from 1%-4% of the population. Although polyps seem to be a manifestation of chronic inflammation of nasal/paranasal sinus mucosa in both allergic and non-allergic subjects, the pathogenesis of nasal polyposis remains unknown. Interleukin-17A (IL-17A) is a key inflammatory cytokine in many disorders. Little attention has been paid to the role of IL-17A in chronic inflammatory disorders.

Objective

To investigate the expression of IL-17A in the SNP and verify if this expression is a marker of good or bad prognosis.

Method

Prospective study with 25 patients presenting with SNP were subjected to the immunohistochemistry technique. After a skin prick test, all patients were divided into atopic and nonatopic groups, and asthmatic or non-asthmatic.

Results

The IL-17A expression was observed in both atopic and nonatopic patients. The numbers of IL-17A positive cells were greater in nasal polyps of atopic patients than nonatopic (p = 0.0128).

Conclusion

These results indicate that IL-17A may play an important role in the pathology of SNP. Considering the inflammatory properties of IL-17A, this study suggests that it could increase susceptibility to atopy and asthma.

An automated point-of-care system for immunodetection of staphylococcal enterotoxin B

An automated point-of-care (POC) immunodetection system for immunological detection of staphylococcal enterotoxin B (SEB) was designed, fabricated, and tested. The system combines several elements: (i) enzyme-linked immunosorbent assay-lab-on-a-chip (ELISA-LOC) with fluidics, (ii) a charge-coupled device (CCD) camera detector, (iii) pumps and valves for fluid delivery to the ELISA-LOC, (iv) a computer interface board, and (v) a computer for controlling the fluidics, logging, and data analysis of the CCD data. The ELISA-LOC integrates a simple microfluidic system into a miniature 96-well sample plate, allowing the user to carry out immunological assays without a laboratory. The analyte is measured in a sandwich ELISA assay format combined with a sensitive electrochemiluminescence (ECL) detection method. Using the POC system, SEB, a major foodborne toxin, was detected at concentrations as low as 0.1 ng/ml. This is similar to the reported sensitivity of conventional ELISA. The open platform with simple modular fluid delivery automation design described here is interchangeable between detection systems, and because of its versatility it can also be used to automate many other LOC systems, simplifying LOC development. This new POC system is useful for carrying out various immunological and other complex medical assays without a laboratory and can easily be adapted for high-throughput biological screening in remote and resource-poor areas.